Thursday, October 1, 2009

Testing a Theory: Game-Winning Save - by Big Tex

Okay, so the first draft of this blog died a merciful death when I realized that it sounded like I was writing a scholarly piece for The Scientific Journal of Hockey Statistical Analysis for People Who are to Hockey Statistics as Trekkies are to Star Trek. While anyone who has memorized the Corsi Ratings for the entire 2007-2008 Tampa Bay Lightning roster would’ve eaten that stuff up, I felt that a rather large segment of the hockey-loving populace – about 98% (+/- 2 percentage points) – would stop reading as soon as they hit the first references to sample size and game segment subsets. After a failed attempt to crumple up my monitor and throw it in the wastebasket (in retrospect, I should’ve just opened up a new Word .doc), I began again, in a much more reader-friendly format:

Last season, I watched more hockey than ever before (thank you, NHL Center Ice!). As the season progressed, I became aware of a particular trend, which is summarized best by the following statement:

If a team is trailing by one goal at any point in the 3rd period and takes a shot which beats the goalie but rings off the post, that team (the team which hit the post) loses the game…EVERY SINGLE TIME.

In game after game, I saw this scenario play out. Remember Game Seven of the Stanley Cup Finals? The Penguins’ post came up big in that one. Many a Game-Winning Save was made by an alert goalpost last season…more than I can recall, in fact.

***NOTE: I realize the term, “Game-Winning Save,” is ridiculous, as there’s no such creature. If a goalie stops 24 of 26 shots in a 3-2 win, how can you decide which of his 24 saves was the “GWS”? You can’t. Also, shots which hit the post don’t count as either shots or saves, officially speaking. I’ve decided, however, that GWS is much easier to manage than a Shot Off the Post in a One-Goal Game (SOPOGG), and much more family-friendly than a Post-Interdicted Scoring Shot (PISS)…although the headline, “Heatley takes a PISS in 3rd; Sharks lose to Stars, 4-3” holds a certain appeal…but I digress. Game-Winning Saves they shall be.***

Once I noticed this trend, the three-year-old in me asked the obvious question: Why? Why does hitting a post when down by a goal in the 3rd period guarantee a loss for the shooting team/guarantee a win for the defending team? After much rumination on the subject, I came up with a theory:

A glance at goalie save percentages in the NHL (Chris Osgood excepted) indicates shooters will only beat goalies on about one in ten shots. Factoring in shots off the post reduces goalie save percentages slightly, which improves the shooters’ odds somewhat – say to three in twenty shots. A goalie will only be beaten a finite number of times in a game, so a shot off the post is not merely a save, but a GOAL DENIED…and in a one-goal game, it’s the Game-Winning Save, every time.

This all makes perfect sense to me, but I’ve had all summer to think about it. Starting today – 1 October 09 – I intend to test this theory. All season long, I’m going to keep track of one-goal games I watch in which the trailing team hits a post in the 3rd period. I’ll post the results periodically, or if I can get enough hockey fans to send me the Game-Winning Saves they witness, I’ll find some space on the On Goal Analysis home page to keep a running total. If you’d like to test this theory with me, email me at shotoffthepost@ongoalanalysis.com with the date, teams, final score, and a very brief explanation (if needed), like: 1OCT, VAN 3,CGY 2. 2 posts for CGY. Or, if email is too “20th century” for you, send me a Tweet ( @OGAs_BigTex). And if you should happen to watch a game which proves this theory wrong, I really want to hear about that.

2 comments:

Anonymous
said...

Sometimes, maybe often, a hit goal post is not a shot that beats the goalie; it is a shot that is wide of the target. Do shots that go over the top bar by a millimeter count as shots that beat the goalie? I guess my point is that with no goalie present, a shot off the bar is no goal. These guys train on their angles like crazy, and are usually really good at positioning. I bet most goal post strikes that look like they were missed by the goalie are really a factor of excellent positioning.

Ah, yes - I was waiting for a goalie to respond with the old, "The post was all I gave him to shoot at" argument. ;)

Seriously, it's a good point, and one I considered discussing in my initial blog. There can be no doubt that many shots off the post occur because the goalie was properly positioned. The difference, however, between a shot off the post and a shot just over the crossbar is simple, yet significant:

Sometimes, shots go off the post and IN. The post is part of the goal structure (the target), just like the rim in basketball. If a shot goes off the post and stays out of the net, I see it as a goal denied, whether the shot got past the goalie or was taken at an empty net.

I suppose I could've just written in terms of "scoring chances" or "PRIME scoring chances", but there is no universal agreement on what constitutes a scoring chance. On the other hand, everyone can look at the replay and agree that a particular shot went off the post.

In the end, though, it all comes down to a trend I noticed last season. Does a shot off the post truly decide the game every single time? Well, that's what I saw last season, but I didn't keep count. This season, I'm keeping track of every instance I can, and I look forward to seeing the results, whatever they may be.